Briefly, this commit fixes a missed flaw:
- Cursor tracking is required to replacing shaded pages and adjusting the positions in writing transactions;
- Thus, historically, an internal linked list was maintained for a read-write transactions, but not for a read-only.
For this reason, the API for using cursors should be different for writing and reading transactions;
- However, the libmdbx's API has been significantly improved, including the ability to reuse cursors and a uniform cursors behavior for any kind of transactions.
My mistake is that due to working with MithrilDB, I forgot to make a same changes to libmdbx.
Fixes https://github.com/erthink/libmdbx/issues/272.
The stable release with the hotfix/workaround for a flaw of Linux 4.19 (at least) unified page/buffer cache.
See [issue#269](https://github.com/erthink/libmdbx/issues/269) for more information.
Acknowledgements:
-----------------
- [Simon Leier](https://github.com/leisim) for reporting and testing.
- [Kai Wetlesen](https://github.com/kaiwetlesen) for [RPMs](http://copr.fedorainfracloud.org/coprs/kwetlesen/libmdbx/).
- [Tullio Canepa](https://github.com/canepat) for reporting C++ API issue and contributing.
Fixes:
------
- [Added workaround](https://github.com/erthink/libmdbx/issues/269) for a flaw of Linux 4.19 (at least) unified page/buffer cache.
- [Fixed/Reworked](https://github.com/erthink/libmdbx/pull/270) move-assignment operators for "managed" classes of C++ API.
- Fixed potential `SIGSEGV` while open DB with overrided non-default page size.
- [Made](https://github.com/erthink/libmdbx/issues/267) `mdbx_env_open()` idempotence in failure cases.
- Refined/Fixed pages reservation inside `mdbx_update_gc()` to avoid non-reclamation in a rare cases.
- Fixed typo in a retained space calculation for the hsr-callback.
Minors:
-------
- Reworked functions for meta-pages, split-off non-volatile.
- Disentangled C11-atomic fences/barriers and pure-functions (with `__attribute__((__pure__))`) to avoid compiler misoptimization.
- Fixed hypotetic unaligned access to 64-bit dwords on ARM with `__ARM_FEATURE_UNALIGNED` defined.
- Reasonable paranoia that makes clarity for code readers.
- Minor fixes Doxygen references, comments, descriptions, etc.
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
The three points:
- disentangle C11-atomic fences/barriers and pure-functions (with `__attribute__((__pure__))`) to avoid compiler misoptimization;
- fix hypotetic unaligned access to 64-bit dwords on ARM with `__ARM_FEATURE_UNALIGNED` defined;
- reasonable paranoia that makes clarity for code readers.
The stable release with fixes for large and huge databases sized of 4..128 TiB.
Acknowledgements:
-----------------
- Ledgerwatch, Binance and Positive Technologies teams for reporting, assistance in investigation and testing.
- Alex Sharov for reporting, testing and provide resources for remote debugging/investigation.
- Kris Zyp for Deno support.
New features, extensions and improvements:
------------------------------------------
- Added treating the `UINT64_MAX` value as maximum for given option inside `mdbx_env_set_option()`.
- Added `to_hex/to_base58/to_base64::output(std::ostream&)` overloads without using temporary string objects as buffers.
- Added `--geometry-jitter=YES|no` option to the test framework.
- Added support for [Deno](https://deno.land/) support by [Kris Zyp](https://github.com/kriszyp).
Fixes:
------
- Fixed handling `MDBX_opt_rp_augment_limit` for GC's records from huge transactions (Erigon/Akula/Ethereum).
- [Fixed](https://github.com/erthink/libmdbx/issues/258) build on Android (avoid including `sys/sem.h`).
- [Fixed](https://github.com/erthink/libmdbx/pull/261) missing copy assignment operator for `mdbx::move_result`.
- Fixed missing `&` for `std::ostream &operator<<()` overloads.
- Fixed unexpected `EXDEV` (Cross-device link) error from `mdbx_env_copy()`.
- Fixed base64 encoding/decoding bugs in auxillary C++ API.
- Fixed overflow of `pgno_t` during checking PNL on 64-bit platforms.
- [Fixed](https://github.com/erthink/libmdbx/issues/260) excessive PNL checking after sort for spilling.
- Reworked checking `MAX_PAGENO` and DB upper-size geometry limit.
- [Fixed](https://github.com/erthink/libmdbx/issues/265) build for some combinations of versions of MSVC and Windows SDK.
Minors:
-------
- Added workaround for CLANG bug [D79919/PR42445](https://reviews.llvm.org/D79919).
- Fixed build test on Android (using `pthread_barrier_t` stub).
- Disabled C++20 concepts for CLANG < 14 on Android.
- Fixed minor `unused parameter` warning.
- Added CI for Android.
- Refine/cleanup internal logging.
- Refined line splitting inside hex/base58/base64 encoding to avoid `\n` at the end.
- Added workaround for modern libstdc++ with CLANG < 4.x
- Relaxed txn-check rules for auxiliary functions.
- Clarified a comments and descriptions, etc.
- Using the `-fno-semantic interposition` option to reduce the overhead to calling self own public functions.
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>
This bug triggered only in the DEBUG builds or when the assertion checking is forcibly enabled.
It does not affect any core logic and cannot lead to DB corruption, data loss, and so on.
Fixes https://github.com/erthink/libmdbx/issues/260.
